Nail or spike



8, 1939 A. M. AGNEW 2,168,854

NAIL 0R SPIKE Filed Aug. 12, 1958 14 g iflg INVENTOR Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE Application August 12,

Claims.

This invention relates to nails or spikes, and an object of the invention is to provide a nail or spike in which the tip of a configuration to permit ready alignment with the grain of the 5 wood into which it is to be driven, and which will pierce the surface to the extent of its depth in a straight line and without turning, to lessen the danger of splitting the wood. A further object of the invention resides in the provision of means to subsequently cause the nail or spike to turn slowly as it is driven further, so that the tip will rupture the fibres of the wood beneath the surface to enable suitable barbs on the tip to bite more tightly into the wood, and resist more effectively any stresses which may occur axially of the nail or spike in a direction tending to withdraw same. Further objects of the invention will be apparent throughout the following specification.

In the drawing forming a part of this specification:

Figure 1 is a side elevation of a nail embodying my invention.

Figure 2 is an elevation of the lower end of the nail shown in Figure 1 as viewed at right angles thereto, and,

Figure 3 is a horizontal section taken on the plane of the line 3-3 of Figure l.

The rounded shank of the nail is shown at l0, and is provided with the usual head H at one end. At the opposite end there is formed a fiat tip H! the sides l3 of which are substantially straight, and the edges Id of which are inclined to meet in a point I5. The edges I 4 are cut back to form barbs IS in diametrically opposed relation. These may be arranged in horizontal alignment, but are shown, alternately, as staggered.

A portion of the shank l0 above the barbs I6 is flattened and tapered as at H, and the part of said flattened portion immeditely above the barbs I6 is helically formed, as at 18, by twisting the tip l2 through an arc of 90 degrees, but however, without departing from the flat helicallyfree formation of the tip. Additional barbs 19 may be provided as shown by cutting back the edges of the helical portion of the shank, or the edges above it, to add to the resistance against withdrawal stresses.

It will be seen that my improved nail does not form a smooth helical hole in the wood into which it'is driven, and which it would likewise tend to follow again when withdrawn, but roughens the walls of the hole for the more effective entangling and gripping of the barbs.

1938, Serial No. 224,454

The nail shown and described herein is properly driven by first aligning the major diameter of the thin tip with the grain of the wood. The surface of the wood will then be initially pierced with a straight narrow slot formed parallel with the grain and splitting obviated. As soon as the tip is buried in the wood the helical portion of the shank immediately above the tip will enter, and the nail will then begin to turn slowly with each stroke of the hammer. As the tip descends further it will tear the fibres of the wood under the twisting influence of the helical portion. At each stroke of the hammer the barbs will move progressively across and under the fibres of the wood, the last stroke of the hammer being the effective one to firmly lock the barbs into the wood in substantially a cross grain position beneath the overhanging structure thereof.

Nails or spikes constructed in accordance with my invention have been found to hold more securely than those in which the tips themselves are of helical configuration. Furthermore, should it be desired to completely withdraw the nail, then after the locking grip is initially broken by the application of unusual forces, the resistance is lessened throughout the remainder of the return path, and consequently there is less undesirable destruction of the wood during such return movement than would otherwise occur.

Should the helical formation of the shank of the nail of this invention be carried on clear through the tip l2, then the tendency, when withdrawal stresses are applied, would be for the shank of the nail to follow the same helical path formed when the same was driven, thereby lessening the resistance against removal.

There is indicated in dotted lines in Figure 1 the level of the barb H3 at the right should the tip be cut in a manner to locate both barbs in substantially the same horizontal plane. When, however, the barbs are cut in an angular relation with respect to the axis of the shank H), such resulting staggering removes two angles of weakness from directly opposite relationship, and thereby increases the resistance of the nail to distortion or breakage under twisting stresses which will then be active along the plane of the dotted line A-A in Figure 1 which is of greater cross sectional area.

Also having the barbs thus disposed in accord ance with this preferred structure enables them to respectively rupture the fibres of the wood in helical planes of greater separation than when disposed directly opposite each other, and thus increase the holding power of the nail.

I claim:

1. A nail comprising a shank having a flattened portion constituting a pointed tip, and provided with diametrically disposed barbs on the edges thereof, said shank also having a flattened portion above said barbs in a plane at an angle to that of said tip and substantially parallel with the axis of said nail, and a helical portion connecting said tip and the other flattened portion of said shank.

2. A nail comprising a shank having a fiattened portion constituting a pointed tip, and provided with diametrically disposed barbs on the edges thereof, said shank also having a flattened portion above said barbs in a plane substantially at aright angle to that of said tip and parallel with the axis of said nail, a helical portion connecting said tip and the other flattened portion of said shank, and a barb on an edge of one of said latter portions.

3. A nail comprising a shank having a flattened portion constituting a pointed tip, and provided with diametrically disposed barbs on the edges thereof, said shank also having a flattened portion above said barbs in a plane substantially at a right angle to that of said tip and parallel with the axis of said nail, a helical portion connecting said tip and the other flattened portion of said shank, and the latter portion having a barb on an edge thereof.

4;. A nail comprising a shank having a flattened portion constituting a pointed tip and provided with diametrically disposed barbs on the edges thereof, said shank also having a flattened portion above said barbs in a plane substantially at a right angle to that of said tip and parallel with the axis of said nail, a helical portion connecting said tip and the other flattened portion of said shank, the latter portion and said helical portion having a barb on an edge thereof respectively.

5. A nail comprising a shank having a fiattened portion constituting a pointed tip, and provided with diametrically disposed barbs on the edges thereof in staggered relation to each other, said shank also having a flattened portion above said barbs in a plane substantially at a right angle to that of said tip and parallel with the axis of said nail, a helical portion on said shank connecting said tip and the other flattened por tion of said shank, the latter portion and said helical portion having a barb on an edge thereof respectively.

ARTHUR M. AGNEW. 

